A busy Emergency Medical Services (EMS) crew may handle as many as 20 calls during the work shift. Typically one or more such calls involve moving a patient from a field location, such as his home or the scene of an accident, to a health care facility such as an emergency room at a hospital.
Providing transport for the patient involves various procedures for appropriately securing the patient in different transport vehicles for transport to the hospital or other appropriate destination. Such transport involves a constant risk to the EMS crew and to the patient. The risk arises from the activity involving the EMS crew, usually two persons, lifting and moving the patients. There is also the danger that the patient may be dropped or roughly handled while being moved. As for the EMS crew, they are routinely faced with lifting situations which can and often do result in significant and even crippling back injuries. This can occur either because of the repetitive lifting of average size patients or occasional lifting of large patients.
The dangers of lifting-related injury is compounded because an EMS crew must lift a patient approximately 7 times during the course of a call. For example, for lifting purposes only, in an emergency involving a 200 lb. man the crew will typically: 1) lift the patient to a mobile, wheeled device placed at its lowest height adjustment; 2) lift the device and patient to the maximum height adjustment, and then move the device and patient to an ambulance; 3) lower the device and patient back to the lowest height adjustment; 4) lift the device and patient into the ambulance; 5) upon arrival at the medical facility, remove the device and patient from the ambulance and lower them to the ground; 6) again, lift the device and patient to the maximum height adjustment, and then move the device and patient into the facility; and 7) lift to transfer the patient from the device to a bed at the facility. During this very typical call the crew has lifted or lowered the patient seven times, thereby doing an amount of work equivalent to lifting more than 1400 pounds when the weight of the device is included.
A particularly difficult part of this process results from the fact that the typical device that is used in the field, e.g., a stretcher for transfer of patients via ambulances, is not well-designed for lifting and lowering. Because of the location of the undercarriage and supporting structure, the members of the EMS crew cannot simply stand on each side of the device and lift or lower it using proper lifting techniques with their legs. Rather, to avoid hitting the undercarriage with their knees, they must turn their bodies sideways, imposing a torquing motion on their backs as they lift and lower. This consequence results in a significant number of disabling back injuries to EMS personnel each year. In addition, because of the strength that is required to lift and lower a device with this type of motion, smaller people, are effectively precluded from working as emergency medical technicians.
Wheeled cots have changed little since their advent approximately sixty years ago. The advent of the “one and a half man” cot in the late 1980s changed the way the patients were loaded and unloaded from the transport vehicle. The “one and a half man” cot has loading wheels at the head of the cot which are placed on the bed of the transport vehicle. In order to load the cot, one crew member supports the cot by the foot end while the other crew member reaches under the cot to manually retract the undercarriage. The cot is then pushed into the transport vehicle by one or both EMS crew members. The reverse occurs at the receiving facility, where the cot is pulled out of the patient compartment until only the loading wheels are in the transport vehicle. While one crew member supports the weight of the patient and cot at the foot end, the other crew member again reaches under the cot and manually lowers the undercarriage. This process is fraught with risk for both the EMS crew and the patient.
The loading height of a vehicle is the dimension measured from the ground to the floor surface of the patient compartment of the vehicle. Many transport vehicles have loading heights that far exceed the approximately 30 inches associated with van type ambulances. For example, a loading height of 35 inches is not uncommon. The result is that the loading wheels of the commonly used manual type cots do not reach the floor of the transport vehicle. In order to facilitate loading, the crew performs a lifting maneuver much like a shoulder shrug to lift the heavy end of the cot where the loading wheels are located into the compartment. Serious injuries to the shoulder joint are a common result of this effort. The patient is also at risk during this maneuver if the cot tips or falls, or if only one wheel of the cot engages the floor of the transport vehicle.
Cots have also been limited by their weight to more compact sizes, making them even less suitable for transporting patients into and out of vehicles having high loading heights.
Further, the cots occasionally collapse, particularly if the patient is heavy, causing the patient to suffer a sudden drop. When the EMS crew member attempts to prevent the cot from collapsing or tipping, the crew member can be injured by being struck by the cot.
Several transport devices with lift-assisted mechanisms have been proposed. One example of such a device is found in U.S. Pat. No. 2,833,587 to Saunders which discloses an adjustable height gurney which includes power cylinders provided in the legs of the upper frame and connected to two of the intersecting lever arms (one on each side of the gurney). To operate the cylinders, the EMS technician repeatedly works the handle of a grip up and down to actuate the hydraulic pump. As an alternative, a valve connects the power cylinders to the fluid reservoir, which valve may be opened by a hand lever connected thereto. Both mechanisms for actuating the hydraulic pump cause problems in operation. Use of the handle, which requires repeatedly working the handle up and down is time consuming and be quite difficult when a patient is on a gurney. To remove the gurney from the ambulance, or to place it in the ambulance, the EMS technicians lifts the stretcher, and the patient, from the ambulance to the ground, and visa versa, after which the technicians can use the grip or hand lever to raise the upper carriage.
Another example is set forth in U.S. Pat. No. 5,022,105, which provides a mobile lift-assisted patient transport device. Another example is presented in application Ser. No. 09/863,324, filed on May 24, 2001.